the problem is that when i start my car and its sitting there idling at around 700rpms the engine starts to move side to side very hard to the point that the whole car shakes. what do u think the problem is ?????? in the rpms also start to go from 700-300 rpms like the car is geting ready to cut out???????????

 

how does it drive? If it seems to drive ok then its prolly an intake leak and tune up stuff.

 

check for vacuum leaks with a can of starting fluid. IF it revs up while you spray it, youve found a leak.

IF you find none, it needs to be idled up. Adjust the idle up to around 800-900 and it should smooth out. Stock idle is 750, but some older engines with lower compressio need to be idled up a bit to keep a smooth idle.